Scanner made from semiconducting nanoparticles coatings

PORTLAND, Ore.  Matsushita Electric Industrial Co. unveiled its nanoparticle-enabled biomedical optical scanner this week at the Society for Biomolecular Screening annual meeting here. The scanner was developed as part of a joint venture with Quantum Dot Corp. (Hayward, Calif.).

The optical scanner, developed by Mitsubishi's Panansonic unit, uses nanoparticles coded as genes in this initial biomedical application. By mixing a batch of nanoparticles with an unknown substance, the genes and other items of interest are scanned by fluorescing when exposed to ultraviolet light.

"By using our custom-engineered quantum dots inside Panasonic's Mosaic Scanner, they get a scanner that is less expensive, but which nevertheless has better sensitivity," said vice president Andy Watson.

Quantum Dot's nanoparticles, which it calls Qdots, use a semiconducting core (CdSe) encased in a second semiconducting shell (ZnS)  imparting the ability to evoke quantum confinement effects including fluorescing.

To make the nanoparticle into a fluorescenct labeling reagent, a polymer coating is applied that is "friendly" to the final "functionalizing" coating. The coating then acts as a lock whose key is whatever item of interest is the target. For
instance, Panasonic's Mosaic Scanner can test for 200 different genes simultaneously.

Panasonic plans a Mosaic System family a bioanalysis devices,
for specific applications in genotyping, protein analysis and cell analysis. Quantum Dot also supplies its nanoparticles to semiconductor researchers researching, for instance, plastic LEDs through the use embedded fluorescing nanoparticles.

"We have over a thousand customers, and while most are doing things like drug discovery, we also have many semiconductor researchers using our quantum dots because they find their experiments are more [reproducible] when they use ours rather than make their own," said Watson.

All Qdots use the quantum confinement phenomenon to fluoresce in the presence of ultraviolet light. Quantum confinement
dictates that ultraviolet photons absorbed by nanoparticles will shift in frequency when emitted. This happens because there is not enough room inside the nanoparticle to contain a complete cycle of long ultraviolet wavelengths.

Quantum Dot's nanoparticles range from just under 2 nm to 5 nm in diameter and are available in five colors ranging from the largest red ones down to orange, yellow, green and the smallest blue ones.